Bay is a hair coat color of horses, characterized by a reddish-brown body color with a black mane, tail, ear edges, and lower legs. Bay is one of the most common coat colors in many horse breeds. The black areas of a bay horse's hair coat are called "black points", and without them, a horse cannot be a bay. Black points may sometimes be covered by white markings; however such markings do not alter a horse's classification as "bay". Bay horses have dark skin, except under white markings - where the skin is pink. Genetically, bay occurs when a horse carries both the Agouti gene and a black base coat. The addition of other genes creates many additional coat colors. While the basic concepts behind bay coloring are fairly simple, the genes themselves and the mechanisms that cause shade variatio